The present invention relates generally to an arrangement for detecting the position of a movable body, especially the angular position of a rotatable body. More particularly, the invention relates to an arrangement of this type in which the body has a plurality of tracks of markings thereon. The markings are distributed along and among the tracks in accordance with a predetermined code. The distribution of the markings may be such that the markings of the individual tracks respectively represent the digits of binary numbers indicating the momentary positions of the body. An arrangement for detecting the presence of the markings includes at least one signal generator and one signal receiver, as well as at least one signal transmitting channel which is controlled by the markings and extends between the signal generator and the signal receiver.
Various arrangements for the determination of the positions of movable bodies are already known, and some of them include a disc-shaped marking carrier or body which is provided with a plurality of annular, concentric tracks of markings. An arrangement of this type is described, for instance, in Steinbuch, "Taschenbuch der Nachrichtenverarbeitung" published by Springer-Verlag, 1962, Page 761. In this publication, the markings are constituted by electrically conductive track sections, and a source of electrical signals is provided as a common signal generator. This conventional arrangement further includes sliding contacts associated with the individual rows or tracks of the markings, as well as an associated signal conduit for each of the sliding contacts which serves as a signal-transmitting channel. Furthermore, this arrangement includes an individual signal receiver such as a relay or the like for each of the marking tracks. This conventional arrangement operates on the basis of parallel scanning of the markings and has a plurality of receivers which are arranged in parallelism with one another. Binary numbers constituting the coded position signal are generated in parallelism at the outputs of the respective receivers. In the event that it is desired to convert the parallel representation of the coded position signal into a series representation it is necessary to connect a parallel-to-serial converter to the outputs of the individual receivers.
The known arrangements for determining the position of a movable or rotatable body by the parallel scanning of marking tracks have relatively complicated circuitry due to the employment of multiple receivers and the fact that conversion of the parallel signals or numbers into serial signals or numbers may be required.